Lifting jack



Aug. 22, 19 39. F. v. POVANDRA LIFTING JACK F'iled'April 22, 1938 2Sheets-Sheet 1 N\ MN WM W.

ATTORNEYS Aug. 22, 1939.

LIFTING Filed April F. v. POVANDRA JACK 22, 1958 2 Sheets-Sheet 2 .Z'ZZZL J 2/ $25 37 5 Frail 1/ Pm/anJ/u 7 Z6 INVENTOR ATTORNEYS PatentedAug. 22, 1939 "UNITED STATES PATENT OFFICE 2 Claims.

My invention relates to lifting jacks and more particularly to that typewherein a plurality of pivoted members are employed for Varying thelifting height.

One of the principal objects of my invention is to provide a liftingjack equipped with a plurality of pivoted members operable for varyingthe height thereof.

Another object of my invention is to provide a'jack of'the' abovedescribed character which is simple in construction, durable in use,efficient in operation and economical in manufacture.

Other objects and advantages will be apparent from the followingdescription, appended claims and annexed drawings.

Referring to the drawings wherein like reference characters designatelike parts throughout the several views:

Figure 1 is a top plan view of my invention illustrating the supportcasing in section.

Figure 2 is a rear elevation, several of the parts being removed.

Figure 3 is a sectional view taken on the line 3-3 of Figure 2.

Figure 4 is a sectional View taken on the line 4-4 of Figure 3.

Figures 5, 6 and '7 are detail sectional views taken on the lines 5-5,66 and l1 of Figure 4 respectively.

Figures 8 and 9 are detail sectional views taken on the lines 88 and 99of Figure 1 respectively.

In practicing my invention I employ a base 5 integrally formed with ahollow support casing 6 having vertically and horizontally extendingchannels 6a and 61) respectively in which is slidably mounted aplurality of articulated members I. Said channels are connected togetherby an inflected section whereby to permit said members to be disposed inaligned position in said channels.

The articulated members I are each in the form of a link having a blockportion 8 fashioned on an outer face with rack teeth 9 for engagementwith gear teeth of a gear l0 fixed to a shaft ll journaled in a bearingl2 mounted on the casing 6 and a bearing l3 mounted on the base 5.

The links are also fashioned with bifurcated end portions for receivingreduced portions of the adjacent links and through which extend pintlesI 4 whereby the links are pivotally connected together. The sides of thelinks are provided with wear plates l5 secured thereto by means of thepintles l4 and said wear plates are fashioned with slots l6 forembracing the ends of latch actuating members ll. The actuating membersI! extend through the block portions 8 and are fashioned with offsetsections l8 operable within transversely extending slots l9 formed insaid portions 8. The block portions 6 8- are also fashioned withlongitudinallyextending bores 20 having latch bolts 2! slidable therein.

Said latch bolts are provided with apertured headsZZ through-whichextend the offset sections l8 of the members IT. The latch bolts areadapt- 10: ed to extend beyond the bores 20 and seat within similarbores 23 formed in the reduced portion of the adjacent link whereby tomaintain the links in aligned position as hereinafter more fullydescribed.

Formed on the members l1, within the slots l9, are yokes 24 havingsliding connections with the ends of coil springs 25, the opposite endsof said springs being connected to the respective reduced portions bymeans of pins 26 as clearly 20 illustrated in Figures 4 and '7 of thedrawings. The outer ends of the members I! are offset and extend atright angles relative to each other for engagement with projections 21and 28 formed on the inner walls of the channel 6a.

The projection 21 extends in the path of one of the offset ends of themembers I! and engages the latter to actuate the latch bolt intoprojected position when the links are moved upwardly within the channel6a by the action of the gear 30 I0. When the gear I0 is operated in areverse direction the projection 28 engages the opposite ends of themembers I! when the links are moved downwardly thereby actuating thelatch bolt to retracted position. As the links are moved up- 35 wardlyin the channel to, the latch bolts are actuated to extended position toeffect latching of the links with each other thereby preventing thelinks or members H from pivoting as they are moved upwardly out of thecasing 6.

The base 5 is provided with a pair of bearings 29 in which is journaleda shaft 30 having fixed thereon a gear 3! meshing with a gear 32 fixedon the shaft ll through the medium of which the gear I 0 and members Iare actuated. Also 45 fixed on the shaft 30 is a bevel gear 33 meshingwith a similar gear 34 rotatably mounted on a shaft 35 and havingconnected thereto for movement therewith a brake drum 36 about which ispositioned a brake band 31. 50

The shaft 35 is rotatably mounted in bearings 38 and has slidablyconnected thereon a clutch element 39 for engagement with a similarelement 40 carried by the gear 34 whereby to connect said gear 34 andsaid brake drum 36 in operating condition with the shaft 35. A spring 4|is mounted on the shaft 35 and interposed between the clutch element 39and the adjacent bearing 38 whereby to normally urge the clutch element39 towards the element 40. An operating arm 42 connects the clutchelement 39 to a shift arm 43, said shift arm being fashioned with aplurality of position grooves 44 in which a roller 45 is adapted toselectively seat.

The roller 45 is rotatably mounted within a yoke 46 carried on one endof an arm 4'! for actuating the brake band 31. The brake band 31 isfashioned with laterally extending spaced ends 48 and 49 connectedtogether by means of a spring 58 for normally maintaining the brake incontracted condition about the drum.

The end 49 of the band is secured to a bracket mounted on the base 5.Each of the ends are provided with openings through which the arm 41extends. The arm 41 is provided with a collar 52 for engaging the underface of the end 48 whereby when the arm 43 is shifted to raise the yoke45, said collar will engage the end 48 and release the band 31 about thedrum 36. Obviously, shifting of the arm 43 serves. to effect engagementof the clutch elements and a release of the brake drum. Shifting of thearm in an opposite direction serves to disengage the clutch elements andpermit application of the brake. Further, shifting of the arm 43 to movethe clutch elements still further apart serves to release the brakewithout effecting engagement of the clutch elements thereby permitting alowering of the members 1 within the channel 6a. The shaft 35 isprovided with end sections for receiving a crank or other similar toolfor operating the device. However, it is to be understood that any othersource of power, other than manual, may be used for operating the shaft35.

The ends of the arm 43 are slidably mounted in bearings 53 secured tothe base 5 whereby the arm 43 is maintained in the bearings 53 againstvertical and lateral movement.

What I claim is:

1. A device of the character described, comprising, a base fashionedwith a casing formed with a pair of connected channels, a plurality ofarticulated members movable in said channels, means for moving saidmembers from one to another of said channels, latching devices carriedwithin said members and equipped with elements extending through saidmembers and terminating in angularly disposed ends without said members,and a projection formed on said casing within one of said channels forengagement with said ends whereby to operate said devices formaintaining said members in aligned condition after movement from onechannel to another.

2. A device of the character described, comprising, a base fashionedwith a casing formed with a pair of connected channels, a plurality ofarticulated members movable in said channels, means for moving saidmembers from one to another of said channels, latching devices operablefor maintaining said members in aligned condition after movement fromone channel to another, and a fixed projection on said casing anddisposed in one of said channels for engagement with said devices foroperating the latter.

FRANK V. POVANDRA.

